Arterial blood pressure is controlled by vasodilatory factors such as nitric oxide (NO) that are released from the endothelium under the influence of fluid shear stress exerted by flowing blood. Flow-induced endothelial release of ATP and subsequent activation of Gq/G11–coupled purinergic P2Y2 receptors have been shown to mediate fluid shear stress–induced stimulation of NO formation. However, the mechanism by which fluid shear stress initiates these processes is unclear. Here, we have shown that the endothelial mechanosensitive cation channel PIEZO1 is required for flow-induced ATP release and subsequent P2Y2/Gq/G11–mediated activation of downstream signaling that results in phosphorylation and activation of AKT and endothelial NOS. We also demonstrated that PIEZO1-dependent ATP release is mediated in part by pannexin channels. The PIEZO1 activator Yoda1 mimicked the effect of fluid shear stress on endothelial cells and induced vasorelaxation in a PIEZO1-dependent manner. Furthermore, mice with induced endothelium-specific PIEZO1 deficiency lost the ability to induce NO formation and vasodilation in response to flow and consequently developed hypertension. Together, our data demonstrate that PIEZO1 is required for the regulation of NO formation, vascular tone, and blood pressure.
ShengPeng Wang, Ramesh Chennupati, Harmandeep Kaur, Andras Iring, Nina Wettschureck, Stefan Offermanns
Carcinoma cells can acquire increased motility and invasiveness through epithelial-to-mesenchymal transition (EMT). However, the significance of EMT in cancer metastasis has been controversial, and the exact fates and functions of EMT cancer cells in vivo remain inadequately understood. Here, we tracked epithelial cancer cells that underwent inducible or spontaneous EMT in various tumor transplantation models. Unlike epithelial cells, the majority of EMT cancer cells were specifically located in the perivascular space and closely associated with blood vessels. EMT markedly activated multiple pericyte markers in carcinoma cells, in particular PDGFR-β and N-cadherin, which enabled EMT cells to be chemoattracted towards and physically interact with endothelium. In tumor xenografts generated from carcinoma cells that were prone to spontaneous EMT, a substantial fraction of the pericytes associated with tumor vasculature were derived from EMT cancer cells. Depletion of such EMT cells in transplanted tumors diminished pericyte coverage, impaired vascular integrity, and attenuated tumor growth. These findings suggest that EMT confers key pericyte attributes on cancer cells. The resulting EMT cells phenotypically and functionally resemble pericytes and are indispensable for vascular stabilization and sustained tumor growth. This study thus proposes a previously unrecognized role for EMT in cancer.
Anitha K. Shenoy, Yue Jin, Huacheng Luo, Ming Tang, Christine Pampo, Rong Shao, Dietmar W. Siemann, Lizi Wu, Coy D. Heldermon, Brian K. Law, Lung-Ji Chang, Jianrong Lu
Angiopoietin-2 (ANG2) regulates blood vessel remodeling in many pathological conditions through differential effects on Tie2 signaling. While ANG2 competes with ANG1 to inhibit Tie2, it can paradoxically also promote Tie2 phosphorylation (p-Tie2). A related paradox is that both inactivation and overactivation of Tie2 can result in vascular remodeling. Here, we reconciled these opposing actions of ANG2 by manipulating conditions that govern its actions in the vasculature. ANG2 drove vascular remodeling during
Minah Kim, Breanna Allen, Emilia A. Korhonen, Maximilian Nitschké, Hee Won Yang, Peter Baluk, Pipsa Saharinen, Kari Alitalo, Christopher Daly, Gavin Thurston, Donald M. McDonald
The angiopoietin/Tie (ANG/Tie) receptor system controls developmental and tumor angiogenesis, inflammatory vascular remodeling, and vessel leakage. ANG1 is a Tie2 agonist that promotes vascular stabilization in inflammation and sepsis, whereas ANG2 is a context-dependent Tie2 agonist or antagonist. A limited understanding of ANG signaling mechanisms and the orphan receptor Tie1 has hindered development of ANG/Tie-targeted therapeutics. Here, we determined that both ANG1 and ANG2 binding to Tie2 increases Tie1-Tie2 interactions in a β1 integrin–dependent manner and that Tie1 regulates ANG-induced Tie2 trafficking in endothelial cells. Endothelial Tie1 was essential for the agonist activity of ANG1 and autocrine ANG2. Deletion of endothelial
Emilia A. Korhonen, Anita Lampinen, Hemant Giri, Andrey Anisimov, Minah Kim, Breanna Allen, Shentong Fang, Gabriela D’Amico, Tuomas J. Sipilä, Marja Lohela, Tomas Strandin, Antti Vaheri, Seppo Ylä-Herttuala, Gou Young Koh, Donald M. McDonald, Kari Alitalo, Pipsa Saharinen
Dysregulation of vascular stiffness and cellular metabolism occurs early in pulmonary hypertension (PH). However, the mechanisms by which biophysical properties of the vascular extracellular matrix (ECM) relate to metabolic processes important in PH remain undefined. In this work, we examined cultured pulmonary vascular cells and various types of PH-diseased lung tissue and determined that ECM stiffening resulted in mechanoactivation of the transcriptional coactivators YAP and TAZ (WWTR1). YAP/TAZ activation modulated metabolic enzymes, including glutaminase (GLS1), to coordinate glutaminolysis and glycolysis. Glutaminolysis, an anaplerotic pathway, replenished aspartate for anabolic biosynthesis, which was critical for sustaining proliferation and migration within stiff ECM. In vitro, GLS1 inhibition blocked aspartate production and reprogrammed cellular proliferation pathways, while application of aspartate restored proliferation. In the monocrotaline rat model of PH, pharmacologic modulation of pulmonary vascular stiffness and YAP-dependent mechanotransduction altered glutaminolysis, pulmonary vascular proliferation, and manifestations of PH. Additionally, pharmacologic targeting of GLS1 in this model ameliorated disease progression. Notably, evaluation of simian immunodeficiency virus–infected nonhuman primates and HIV-infected subjects revealed a correlation between YAP/TAZ–GLS activation and PH. These results indicate that ECM stiffening sustains vascular cell growth and migration through YAP/TAZ-dependent glutaminolysis and anaplerosis, and thereby link mechanical stimuli to dysregulated vascular metabolism. Furthermore, this study identifies potential metabolic drug targets for therapeutic development in PH.
Thomas Bertero, William M. Oldham, Katherine A. Cottrill, Sabrina Pisano, Rebecca R. Vanderpool, Qiujun Yu, Jingsi Zhao, Yiyin Tai, Ying Tang, Ying-Yi Zhang, Sofiya Rehman, Masataka Sugahara, Zhi Qi, John Gorcsan III, Sara O. Vargas, Rajan Saggar, Rajeev Saggar, W. Dean Wallace, David J. Ross, Kathleen J. Haley, Aaron B. Waxman, Victoria N. Parikh, Teresa De Marco, Priscilla Y. Hsue, Alison Morris, Marc A. Simon, Karen A. Norris, Cedric Gaggioli, Joseph Loscalzo, Joshua Fessel, Stephen Y. Chan
Macrophages contribute to the development of atherosclerosis through pinocytotic deposition of native LDL–derived cholesterol in macrophages in the vascular wall. Inhibiting macrophage-mediated lipid deposition may have protective effects in atheroprone vasculature, and identifying mechanisms that potentiate this process may inform potential therapeutic interventions for atherosclerosis. Here, we report that dysregulation of exon junction complex–driven (EJC-driven) mRNA splicing confers hyperpinocytosis to macrophages during atherogenesis. Mechanistically, we determined that inflammatory cytokines induce an unconventional nonproteolytic calpain, calpain-6 (CAPN6), which associates with the essential EJC-loading factor CWC22 in the cytoplasm. This association disturbs the nuclear localization of CWC22, thereby suppressing the splicing of target genes, including those related to Rac1 signaling. CAPN6 deficiency in LDL receptor–deficient mice restored CWC22/EJC/Rac1 signaling, reduced pinocytotic deposition of native LDL in macrophages, and attenuated macrophage recruitment into the lesions, generating an atheroprotective phenotype in the aorta. In macrophages, the induction of CAPN6 in the atheroma interior limited macrophage movements, resulting in a decline in cell clearance from the lesions. Consistent with this finding, we observed that myeloid CAPN6 contributed to atherogenesis in a murine model of bone marrow transplantation. Furthermore, macrophages from advanced human atheromas exhibited increased CAPN6 induction and impaired CWC22 nuclear localization. Together, these results indicate that CAPN6 promotes atherogenicity in inflamed macrophages by disturbing CWC22/EJC systems.
Takuro Miyazaki, Kazuo Tonami, Shoji Hata, Toshihiro Aiuchi, Koji Ohnishi, Xiao-Feng Lei, Joo-ri Kim-Kaneyama, Motohiro Takeya, Hiroyuki Itabe, Hiroyuki Sorimachi, Hiroki Kurihara, Akira Miyazaki
Pulmonary arterial hypertension (PAH) is a life-threatening disease that can be induced by dasatinib, a dual Src and BCR-ABL tyrosine kinase inhibitor that is used to treat chronic myelogenous leukemia (CML). Today, key questions remain regarding the mechanisms involved in the long-term development of dasatinib-induced PAH. Here, we demonstrated that chronic dasatinib therapy causes pulmonary endothelial damage in humans and rodents. We found that dasatinib treatment attenuated hypoxic pulmonary vasoconstriction responses and increased susceptibility to experimental pulmonary hypertension (PH) in rats, but these effects were absent in rats treated with imatinib, another BCR-ABL tyrosine kinase inhibitor. Furthermore, dasatinib treatment induced pulmonary endothelial cell apoptosis in a dose-dependent manner, while imatinib did not. Dasatinib treatment mediated endothelial cell dysfunction via increased production of ROS that was independent of Src family kinases. Consistent with these findings, we observed elevations in markers of endothelial dysfunction and vascular damage in the serum of CML patients who were treated with dasatinib, compared with CML patients treated with imatinib. Taken together, our findings indicate that dasatinib causes pulmonary vascular damage, induction of ER stress, and mitochondrial ROS production, which leads to increased susceptibility to PH development.
Christophe Guignabert, Carole Phan, Andrei Seferian, Alice Huertas, Ly Tu, Raphaël Thuillet, Caroline Sattler, Morane Le Hiress, Yuichi Tamura, Etienne-Marie Jutant, Marie-Camille Chaumais, Stéphane Bouchet, Benjamin Manéglier, Mathieu Molimard, Philippe Rousselot, Olivier Sitbon, Gérald Simonneau, David Montani, Marc Humbert
Renal preglomerular arterioles regulate vascular tone to ensure a large pressure gradient over short distances, a function that is extremely important for maintaining renal microcirculation. Regulation of renal microvascular tone is impaired in salt-sensitive (SS) hypertension–induced nephropathy, but the molecular mechanisms contributing to this impairment remain elusive. Here, we assessed the contribution of the SH2 adaptor protein p66Shc (encoded by
Bradley Miller, Oleg Palygin, Victoriya A. Rufanova, Andrew Chong, Jozef Lazar, Howard J. Jacob, David Mattson, Richard J. Roman, Jan M. Williams, Allen W. Cowley Jr., Aron M. Geurts, Alexander Staruschenko, John D. Imig, Andrey Sorokin
The lymphatic vasculature is essential for maintaining interstitial fluid homeostasis, and dysfunctional lymphangiogenesis contributes to various pathological processes, including inflammatory disease and tumor metastasis. Mutations in
Anees Fatima, Ying Wang, Yutaka Uchida, Pieter Norden, Ting Liu, Austin Culver, William H. Dietz, Ford Culver, Meredith Millay, Yoh-suke Mukouyama, Tsutomu Kume
Lymphangiogenesis is supported by 2 homologous VEGFR3 ligands, VEGFC and VEGFD. VEGFC is required for lymphatic development, while VEGFD is not. VEGFC and VEGFD are proteolytically cleaved after cell secretion in vitro, and recent studies have implicated the protease a disintegrin and metalloproteinase with thrombospondin motifs 3 (ADAMTS3) and the secreted factor collagen and calcium binding EGF domains 1 (CCBE1) in this process. It is not well understood how ligand proteolysis is controlled at the molecular level or how this process regulates lymphangiogenesis, because these complex molecular interactions have been difficult to follow ex vivo and test in vivo. Here, we have developed and used biochemical and cellular tools to demonstrate that an ADAMTS3-CCBE1 complex can form independently of VEGFR3 and is required to convert VEGFC, but not VEGFD, into an active ligand. Consistent with these ex vivo findings, mouse genetic studies revealed that ADAMTS3 is required for lymphatic development in a manner that is identical to the requirement of VEGFC and CCBE1 for lymphatic development. Moreover, CCBE1 was required for in vivo lymphangiogenesis stimulated by VEGFC but not VEGFD. Together, these studies reveal that lymphangiogenesis is regulated by two distinct proteolytic mechanisms of ligand activation: one in which VEGFC activation by ADAMTS3 and CCBE1 spatially and temporally patterns developing lymphatics, and one in which VEGFD activation by a distinct proteolytic mechanism may be stimulated during inflammatory lymphatic growth.
Hung M. Bui, David Enis, Marius R. Robciuc, Harri J. Nurmi, Jennifer Cohen, Mei Chen, Yiqing Yang, Veerpal Dhillon, Kathy Johnson, Hong Zhang, Robert Kirkpatrick, Elizabeth Traxler, Andrey Anisimov, Kari Alitalo, Mark L. Kahn